1. Technical Field
An embodiment of the invention relates to a hydraulic pressure supply apparatus for a transmission, particularly to a hydraulic pressure supply apparatus for a transmission in which driving of a vehicle can be ensured without a special device even when a failure of hydraulic line pressure (original control pressure) occurs.
2. Background Art
In a conventional hydraulic pressure supply apparatus, when a solenoid valve fails (breaks down) due to disconnection of a control circuit or solenoid that constitutes a control system of the line pressure, predetermined maximum pressure is supplied to a variable pulley of a CVT to ensure driving of a vehicle, as taught, for example, by Japanese Patent No. 3116808 ( '808).
In the reference, when the aforementioned failure occurs at high engine speed, since pulley clamping pressure becomes excessive and it leads to the excessive increase in an oil temperature, the engine speed is limited to avoid such inconvenience.